ATMOSPHERIC RADON - ORIGIN AND TRANSFER

Atmospheric indoor and outdoor radon surveys have been performed in se veral locations of Mexico. In order to estimate the radon transfer fro m different origins to the atmosphere, soil and ground water, together with the exhalation rate from bare and coated building materials have also been studied. The radon detection was performed with SSNTD, an a utomatic silicon-based radon monitor and the liquid scintillation tech nique. The results from several years of monitoring indicate that the atmospheric radon behaviour is different for the countryside as compar ed with more complex inhabited regions; transfer from soil being inhib ited by the specific structures of the cities. The effect of wall coat ings reduced from 50% to 90% the radon exhalation from bare building m aterials. A low radon content was observed in the ground water samples studied.